gst-browser: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/gst-browser - from package: gnu-smalltalk-browser

You may install the required package with command apt-get install {package}

Error in other languages:
gst-browser: bevel nie gevind nie
gst-browser: comandă negăsită
gst-browser: comando não encontrado
gst-browser: commande introuvable
gst-browser: command not found
gst-browser: käsku ei ole
gst-browser: không tìm thấy lệnh
gst-browser: komanda nerasta
gst-browser: Kommando nicht gefunden.
gst-browser: kommandot finns inte
gst-browser: komut yok
gst-browser: nie znaleziono polecenia
gst-browser: níor aimsíodh an t-ordú
gst-browser: no se encontró la orden
gst-browser: no s'ha trobat l'ordre
gst-browser: opdracht niet gevonden
gst-browser: parancs nem található
gst-browser: perintah tidak ditemukan
gst-browser: príkaz nenájdený
gst-browser: příkaz nenalezen
gst-browser: команда не найдена
gst-browser: командата не е открита
gst-browser: 命令找不到
gst-browser: コマンドが見つかりません